I just realized that I inadvertantly tested the effect of Deep Attunement over in the thread about mana regeration abilities in Magic 3.2:
Cleric - does not know Deep Attunement
Without PoM - goes from 14 to 98 mana% in 203.9250656 seconds for a rate of 0.4119160 mana%/s
Bard - knows Deep Attunement
Self without BotF goes from 13 to 98 mana% in 192.0900059 seconds for a rate of 0.4425008 mana%/s
Moon Mage - knows Deep Attunement
Without Shadowling goes from 14 to 98 mana% in 192.0070037 seconds for a rate of 0.4374840 mana%/s
Since we know that base regen is a fixed percent of attunement pool then the only factor that makes a difference in these cases is the feat. It looks like the base regeneration without the feat is 0.4% of your pool per second which is 2.4% per pulse. With the feat it appears to get a 10% increase to 0.44% of your pool per second which is 2.64% per pulse. This amounts to 42 pulses over 252 seconds to go from 0 to 100 without the feat and 38 pulses over 228 seconds to go from 0 to 100 with the feat.
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